Dynamically toggle between logarithmic and regular scale

HTML

<script type="text/javascript" src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/serial.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/themes/none.js"></script>
<div id="chartdiv"></div>			
<input type="button" value="toggle logarithmic" onclick="toggle();" id="button" />

CSS

body {
    font-family: Verdana;
    font-size: 12px;
    padding: 10px;
}

#chartdiv {
	width	: 100%;
	height	: 500px;
}

#button {
    padding: 10px;
    font-size: 15px;
    position: absolute;
    top: 60px;
    right: 30px;
}

JavaScript

var chart = AmCharts.makeChart("chartdiv", {
    "type": "serial",
    "theme": "none",
     "pathToImages": "http://www.amcharts.com/lib/3/images/",
    "dataProvider": [{
        "date": "2012-03-01",
        "price": 20
    }, {
        "date": "2012-03-02",
        "price": 75
    }, {
        "date": "2012-03-03",
        "price": 15
    }, {
        "date": "2012-03-04",
        "price": 75
    }, {
        "date": "2012-03-05",
        "price": 158
    }, {
        "date": "2012-03-06",
        "price": 57
    }, {
        "date": "2012-03-07",
        "price": 107
    }, {
        "date": "2012-03-08",
        "price": 89
    }, {
        "date": "2012-03-09",
        "price": 75
    }, {
        "date": "2012-03-10",
        "price": 132
    }, {
        "date": "2012-03-11",
        "price": 158
    }, {
        "date": "2012-03-12",
        "price": 56
    }, {
        "date": "2012-03-13",
        "price": 169
    }, {
        "date": "2012-03-14",
        "price": 24
    }, {
        "date": "2012-03-15",
        "price": 147
    }],
    "valueAxes": [{
        "logarithmic": true,
        "dashLength": 1,
        "guides": [{
            "dashLength": 6,
            "inside": true,
            "label": "average",
            "lineAlpha": 1,
            "value": 90.4
        }],
        "position": "left"
    }],
    "graphs": [{
        "bullet": "round",
        "id": "g1",
        "bulletBorderAlpha": 1,
        "bulletColor": "#FFFFFF",
        "bulletSize": 7,
        "lineThickness": 2,
        "title": "Price",
        "type": "smoothedLine",
        "useLineColorForBulletBorder": true,
        "valueField": "price"
    }],
    "chartScrollbar": {},
    "chartCursor": {
        "cursorPosition": "mouse"
    },
   	
    "categoryAxis": {
        "logarithmic" : true; 
    }
});

function toggle() {
    chart.categoryAxes[0].logarithmic = chart.categoryAxes[0].logarithmic ? false : true;
    chart.validateNow();
}